Oregon researchers developing a vaccine that has shown promise in preventing HIV infection in primates said on Wednesday they have been awarded a $25 million grant from the Bill & Melinda Gates Foundation.

Oregon Health & Science University scientists, in announcing the award, said they hope to develop a vaccine that not only prevents the HIV virus from infecting people exposed to it, but also eliminates the virus from those already infected.

The grant follows research published by the scientists seeking to show their vaccine candidate halting the transmission of, or eliminating altogether, a form of the virus in about half of more than 100 monkeys tested.

"In effect, we helped better arm the hunters in the body to chase down and kill an elusive viral enemy," lead researcher Louis Picker wrote in the magazine Nature, which published lab results last year. "And we're quite confident that this vaccine approach can work exactly the same way against HIV in humans."

While the annual number of new HIV infections has declined in recent years, more than 35 million people globally were living with HIV and an estimated 2.1 million people were newly infected with the virus that causes AIDS last year, according to the World Health Organization.

Although AIDS-related deaths have dropped in recent years due to antiretroviral drug therapy, some 1.5 million people still died from the disease last year, the organization said.

In the United States, the annual rate of diagnosis with HIV fell by a third between 2002 and 2011, according to a study in the Journal of the American Medical Association.

The grant will be used over the next five years to establish whether the vaccine can be used safely on humans in a clinical trial and to help Picker develop a version of the vaccine suitable for larger-scale testing, which is required to bring it to market and will take at least a decade.

The grant will largely be used to develop the preventative vaccine, which could also be used for therapeutic and antiretroviral therapies, the university said in a statement.

The National Institutes of Health cited Picker's research among its "promising medical advances" of 2013, the researchers said.

The Bill and Melinda Gates Foundation aims to eradicate the world's most deadly diseases and poverty.